noun: A large, flashy peice of neck jewelry (ie: chain, medallion etc)worn by a male-usually a badass-during sexual intercourse, for the sole purpose of watching the "fuck-chain" swing during sex. "fuck-chains" are most often worn during doggy stlye sex so the fuck-chainer can watch it tap against the ass of the fuck-chainee.
Antonym: bitchlace
"that's a nice fuck-chain man, whered u get it?"
-or-
"you ready to get boned? hold on lemme put my fuck-chain on real quick."
According to Questionable Content it is an esoteric sex act involving electricity, enemas, amniotic fluid and screaming. It is best performed atop a Delorean, but a Firebird will do in a pinch.
"Did you hear that Felicia Day, Adam Savage, and Wil Wheaton were killed while performing a tesla fuckchain at Comic-Con?"